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BSc, MSc, PhD, FRES, MCIEEM
Department of Biological and Medical Sciences
Faculty of Health and Life Sciences
+44 (0)1865 483957
Director of Centre for Ecology, Environment and Conservation. MSc Conservation Ecology course leader.
My research is in the area of insect ecology and phylogeography, using butterflies as model organisms, with a firm commitment to contributing to the evidence base for conservation.
Leader of MSc Conservation Ecology and contributor to undergraduate teaching
Lead for MSc modules:
BIOL7001 Taxonomy and Identification
BIOL7002 Ecology for Conservation
BIOL 7006 Research Project
I supervised c.6 MSc research projects per year
Contributor to UG modules:
BIOL6006 Environmental Change: Field-Work and Research
BIOL6014 Field course: Interpreting Ecological & Environmental complexity (Module lead)
2020 - R. Whitla: Ecological genomics to understand extinction, range contraction, and range expansion in butterfly species.
2015- S. Williams: (part-time): The biogeography and phylogeny of the spider genus Gasteracantha. In conjunction with the Hope Entomological Collections, Oxford University Museum
2015- 2019 J. Middleton-Welling (full-time): Butterfly traits and phylogeography: the responses of evolutionary lineages to environmental change.2014 - 2019 J. Watkins: (part-time): Unintended consequences in conservation: How can predictive assessments of impacts from conservation projects , programmes and actions be made more comprehensive
2014 - 2020 A. George (part-time): Assessment of aspects of the Steart Wetland habitat creation scheme. In collaboration with the Wildfowl and Wetlands Trust and Bridgewater College
My research is within three linked themes:1.The roles of morphology and physiology in limiting species distributions at a range of scales:All species have definable geographic ranges and associations with particular physical and biological elements where they occur. If the reasons for these associations can be understood then efforts to conserve species and predict species occurrences become easier. Using butterflies as model organisms I focus on how morphology (colour, pattern, size and shape) and thermal requirements influences the range of microhabitats and microclimates that species use. I do this using innovative behavioural field studies combined with microclimate recording, body temperature measurements, and morphological analyses. This work is providing direct evidence why invertebrate species may not respond in the same way to environmental change as predicted by conventional climate change modelling; insects respond to much finer grained thermal environments than can be modelled with climate change scenario data. The work also has a very important, and recognised, message for conservation; providing appropriate environments for insects requires heterogeneity of structures to cater for their thermal requirements and their needs to avoid predators, find mates, lay eggs and complete their life-cycle. 2. Determining faunal structures among European butterflies:With colleagues (Uk and International) I have used existing distribution data sets (UKBMS and the European- Electronic Atlas of European Butterflies) to identify hotspots of diversity within Europe where conservation effort should be focused. Using butterflies as examples (primarily because of the quality of the existing data) we have identified species with similar responses to past climatic and landscape events, because these groups have unique distribution patterns and evolutionary dynamics. Recent work on the occurrence of species on the Tuscan, Sicilian and Aegean Islands has identified that within any particular location there is measurable species loss and recolonization over recent time scales and hidden biodiversity; revealed by mitochondrial DNA (mtDNA) analysis. We have extended this work to the British Isles and have identified a diverse and somewhat unexpected pattern of colonization. As with the Mediterranean island there are hidden patterns of biodiversity with some species comprising more than one evolutionary lineage. We are also identifying homogenisation of faunas with recent environmental change. This aspect of the work is partly with Dr Saad Arif and Michael Gerth in which we are using mtDNA, nuclear markers and Wolbachia to reveal genetic structuring that has resulted from multiple coloniztion events. This has implications for conservation prioritising.
3. Linking species attributes to distributions and redefining what habits are:Current threats to a large proportion of the butterflies of Europe mean that species centred conservation programmes are unlikely to be effective for maintaining and enhancing the majority of them as there are insufficient resources and time to adopt such an approach. Instead, I and colleagues are identifying the basic ecological attributes that determine which species should predictably occur together and have similar responses to small and large-scale environmental change. This work was developed within the UK, partly with individuals from the NERC Centre for Ecology and Hydrology (CEH). Knowing species attributes also helps understand what resource sets species need to persist, which trait combinations make some species highly vulnerable to climate and landscape change and which combinations make species very successful in response to current changes. Knowing the key traits of species and their precise resource requirements will provide for evidence based management to maintain species and communities at the landscape and site scales. With UK and International collaborators we have recently produced a comprehensive trait database of the European and Maghreb butterflies, which provides a valuable resource for understanding the importance of the fundamental characteristics of this taxonomc group which influences their responses to environmental changes.
Evolution, Ecology, Environment and Conservation
Invertebrate Ecology and Biogeography
Research has been funded by:
Legambiente Italia (Italian National Parks)
HEIF (Proof of Concept funding)
This book presents a detailed treatment on the butterflies of Britain's and Ireland's offshore islands. The contents divide into two complementary parts. The first is an account of the findings from analyses of data from the islands. In the second part, butterfly records are presented for 219 islands. Both sections are linked to an extensive bibliography and are supported by a checklist of species, numerous figures and tables. Two appendices list rare immigrants and provide advice and sources of information for making observations on the butterflies of islands. Suggestions are made for future research and the main findings are summarized in a concluding section.
The book provides an up-to-date synthesis of butterfly records for Britain's and Ireland's offshore islands. The authors demonstrate the significance of geography and ecology in accounting for the number of species and the incidence of species on islands. The findings have important connotations for understanding the processes of colonization and extinction, with ramifications for butterfly conservation in Britain and Ireland.
The paradigm of isolation in southern refugia during glacial periods followed by expansions during interglacials, producing limited genetic differentiation in northern areas, dominates European phylogeography. However, the existence of complex structured populations in formerly glaciated areas, and islands connected to mainland areas during glacial maxima, call for alternative explanations. We reconstructed the mtDNA phylogeography of the widespread Polyommatus icarus butterfly with an emphasis on the formerly glaciated and connected British Isles. We found distinct geographical structuring of CO1 haplogroups, with an ancient lineage restricted to the marginal European areas, including Northern Scotland and Outer Hebrides. Population genomic analyses, using ddRADSeq genomic markers, also reveal substantial genetic structuring within Britain. However, there is negligble mito-nuclear concordance consistent with independent demographic histories of mitochondrial vs. nuclear DNA. While mtDNA-Wolbachia associations in northern Britain could account for the geographic structuring of mtDNA across most of the British Isles, for nuclear DNA markers (derived from ddRADseq data) butterflies from France cluster between northern and southern British populations – an observation consistent with a scenario of multiple recolonisation. Taken together our results suggest that contemporary mtDNA structuring in the British Isles (and potentially elsewhere in Europe) largely results from Wolbachia infections, however, nuclear genomic structuring suggests a history of at least two distinct colonisations. This two-stage colonisation scenario has previously been put forth to explain genetic diversity and structuring in other British flora and fauna. Additionally, we also present preliminary evidence for potential Wolbachia-induced feminization in the Outer Hebrides.
Trait-based analyses explaining the diferent responses of species and communities to environmental changes are increasing in frequency. European butterfies are an indicator group that responds rapidly to environmental changes with extensive citizen science contributions to documenting changes of abundance and distribution. Species traits have been used to explain long- and short-term responses to climate, land-use and vegetation changes. Studies are often characterised by limited trait sets being used, with risks that the relative roles of diferent traits are not fully explored. Butterfy trait information is dispersed amongst various sources and descriptions sometimes difer between sources. We have therefore drawn together multiple information sets to provide a comprehensive trait database covering 542 taxa and 25 traits described by 217 variables and sub-states of the butterfies of Europe and Maghreb (northwest Africa) which should serve for improved trait-based ecological, conservationrelated, phylogeographic and evolutionary studies of this group of insects. We provide this data in two forms; the basic data and as processed continuous and multinomial data, to enhance its potential usage.
Understanding the dynamics of biodiversity, including the spatial distribution of genetic diversity, is critical for predicting responses to environmental changes, as well as for effective conservation measures. This task requires tracking changes in biodiversity at large spatial scales and correlating with species functional traits. We provide three comprehensive resources to understand the determinants for mitochondrial DNA differentiation represented by i) 15,609 COI sequences and ii) 14 traits belonging to 307 butterfly species occurring in Western‐Central Europe and iii) the first multi‐locus phylogenetic tree of all European butterfly species. By applying phylogenetic regressions we show that mitochondrial DNA spatial differentiation (as measured with Gst, G'st, D and Dst) is negatively correlated with species traits determining dispersal capability and colonization ability. Thanks to the high spatial resolution of the COI data, we also provide the first zoogeographic regionalization maps based on intraspecific genetic variation. The overall pattern obtained by averaging the spatial differentiation of all Western‐Central European butterflies shows that the paradigm of long‐term glacial isolation followed by rapid pulses of post‐glacial expansion has been a pervasive phenomenon in European butterflies. The results and the extensive datasets we provide here constitute the basis for genetically‐informed conservation plans for a charismatic group in a continent where flying insects are under alarming decline.
We examined the roles of wing melanisation, weight, and basking posture in thermoregulation in Polyommatus Icarus, a phenotypically variable and protandrous member of the diverse Polyommatinae (Lycaenidae). Under controlled experimental conditions, approximating to marginal environmental conditions for activity in the field (= infrequent flight, long duration basking periods), warming rates are maximised with fully open wings and maximum body temperatures are dependent on weight. Variation in wing melanisation within and between sexes has no effect on warming rates; males and females which differ in melanisation had similar warming rates. Posture also affected cooling rates, consistent with cooling being dependent on convective heat loss. We hypothesise that for this small sized butterfly, melanisation has little or no effect on thermoregulation. This may be a factor contributing to the diversity of wing colours in the Polyommatinae. Because of the importance of size for thermoregulation in this small butterfly, requirements for attaining a suitable size to confer thermal stability in adults may also be a factor influencing larval feeding rates, development time and patterns of voltinism. Our findings indicate that commonly accepted views of the importance of melanisation, posture and size to thermoregulation, developed using medium and large sized butterflies, are not necessarily applicable to small sized butterflies.
Biotic regionalization provides fundamental information for biogeography and conservation. The current consensus is to couple turnover indices and clustering methods to identify regions with distinct biotic composition. Nevertheless, turnover indices can produce large numbers of zero and tied dissimilarity values generating multiple clustering solutions which vary according to the arbitrary order of cases in the input matrix. Zero and tied values are particularly numerous at mid-small spatial scales where low signals for turnover occur. Turnover patterns can be also obscured by incomplete sampling. We have designed a new method (recluster.region) based on the creation of a new dissimilarity matrix involving a continuous consensus of cell clustering among different random trees. This matrix minimizes the bias produced by zero and tied values before the final clustering. We created virtual data sets with a priori generated turnover areas and compared the power of the new and of classic methods in recognizing regionalization patterns on the basis of several evaluators (consistency among runs, correct attribution, mean silhouette width and explained dissimilarity) for different levels of sampling intensity [collection completeness (CC)]. We also used a real data set of British butterflies recorded for 10 × 10 km2 cells to test our method. All methods were sensitive to the order of cases in the dissimilarity matrix. Some methods (UPGMA, UPGMC, WPGMA, WPGMC and single linkage) also produced ineffective clustering solutions. Our recluster.region procedures had higher consistency compared to classic clustering and performed best in recognizing the a priori determined regions in virtual data sets (mostly when in association with Ward clustering). Moreover, for the real butterfly data set, recluster.region associated with Ward method and to a lesser extent with DIANA and complete linkage resulted in stable solutions, which largely agreed with the distribution of a set of species identified as responsible for generating the turnover pattern. The Ward method also performed best with low CC. Regionalization can be greatly improved by using the recluster.region algorithm. For the data set of butterflies, it clearly revealed the occurrence of three faunistic regions, supporting the existence of a Holocene climatic refuge and a current Anthropocene refuge in northern and western Britain.
Habitat loss and fragmentation, exacerbated by projected climate change, present the greatest threats to preservation of global biodiversity. As increasing habitat fragmentation and isolation of residual fragments exceeds the dispersal capacity of species, there is the growing need to address connectivity to maintain diversity. Traditionally, habitat corridors have been proposed as a solution. But, the concept of corridors (barriers) is poorly understood; typically they are defined as linear habitats linking up habitat patchwork, and are advocated without a detailed understanding of the elements making up species' habitats and the cost-effectiveness of alternative solutions. Yet, landscapes comprise an enormous range of ‘linear' structures that can function in different ways to promote species' persistence and diversity. In this review, a functional definition of corridor (barrier) is developed to give prominence to connectivity as opposed to ad hoc structures purported to advance connectivity. In developing the concept, urgency to accommodate environmental changes compels a growing emphasis on organism diversity rather than a preoccupation with single species conservation. The review, in focusing on butterflies to address the issue of corridors for patchwork connectivity, draws attention to fundamental divisions among organisms in any taxon: generalists and specialists. Both groups benefit from large patches as these necessarily house species with specialist resources as well as generalists with very different resource types. But, generalists and specialists require very different solutions for connectivity, from short-range habitat corridors and gateways for specialists to habitat and resource stepping stones (nodes, surfaces) for generalists. Connectivity over extensive areas is most critical for moderate generalists and their conservation requires emphasis being placed on space-time resource heterogeneity; landscape features, of whatever dimensionality and structure, provide a vital framework for developing the variety of suitable conditions and resources for enhancing their diversity.
Phylogeographical research has revealed several paradigm patterns of postglacial range expansion from the Mediterranean peninsulas to more northern parts of Europe. These range expansions have consequences for the genetic constitution of populations. Although many studies have been performed in mainland Europe, the colonization history of the British Isles is relatively poorly studied; the genetic consequences of the last glacial readvances and the climate optimum conditions, as well as the implications of the recent climatic conditions on the population genetic structures, are little understood. Therefore, we selected the common blue butterfly Polyommatus icarus as a model species for understanding more generally the colonization patterns of the British Isles and the genetic dynamics on these islands. Allozyme analyses of this butterfly show a rather high genetic diversity over continental Europe without major genetic differentiation. The situation on the British Isles is completely different. Here, populations show a much lower genetic diversity compared to mainland Europe. The genetic constitution is well differentiated from that observed on the European mainland, and the genetic differentiation among populations in Britain is stronger than at the European scale. These results support the hypothesis that a relatively cold-tolerant species such as the common blue could have colonized the British Isles early during the late glacial period and survived the last glacial readvances in small refugia in the South. The retraction of this species in small isolated populations could have caused the genetic impoverishment found. The subsequent forest climax during the climate optimum possibly restricted further expansion of this early succession species to small pockets all over the British Isles, resulting in the genetic patchwork that is still observed. Additionally, the relatively cool and rainy conditions one these islands might have caused bottlenecks, possibly enforcing these genetic patterns.
The Convention on Biological Diversity (CBD) was an outcome of the ‘Earth Summit’ held in Rio de Janeiro in 1992. In 2002 the Convention committed the European Union (EU) and (currently) 192 other countries ‘‘to achieve by 2010 a significant reduction of the current rate of biodiversity loss at the global, regional and national level’’ (Anonymous 2010). The EU set an even more ambitious target: ‘‘…to protect and restore habitats and natural systems and halt the loss of biodiversity by 2010…’’ (Anonymous 2001). In March 2010, Butterfly Conservation held its 6th International Symposium on the topic, ‘The 2010 Target and Beyond for Lepidoptera’, to assess progress towards the target, report advances in conservation science, and look to the future. This volume presents a collection of papers from that meeting.
Landscape scale conservation efforts are becoming more commonplace in conservation, with a move from single species to multi-species initiatives. These initiatives are reliant on modelling processes, largely underpinned by metapopulation models. We argue that generic models developed for individual species in particular landscapes over selected time periods may only be applicable to alternative landscapes and time periods in restricted circumstances. Variability in species responses to landscapes and environmental conditions is dependent on a range of species-specific intrinsic characteristics, dependent on their responses to resources, (including weather) and also individual states. We propose that the behavioural component of how species respond to resources needs to be taken into account in modelling species responses to landscape, and therefore how limited resources for conservation are deployed. Species behaviours are inherently complex. We argue that because of this complexity the conservation of the majority of species, especially of the least rare, may be best served if conservation effort is additionally focused on increasing landscape heterogeneity and disturbance. This may also facilitate persistence in the face of climate change. We suggest that heterogeneity should be promoted through agri-environment schemes.
Peat forming wetlands are globally important sources of the greenhouse gas CH(4). The variability of flux recordings from peatlands is however considerable and the distribution of CH(4) below the water table poorly described. Surface peat (0-500 mm below the water table) is responsible for the bulk of emissions and a localised region of intense CH(4) concentration may exist within this region but the structure of peat and presence of gas bubbles make the determination of in situ gas distributions problematic. We report on the in situ distribution and concentrations of CH(4), CO(2) and O(2) in surface bog peat cores using Quadrupole Mass Spectrometry and relate this to peat physical structure. Replicate cores collected in spring and autumn from both hollows and hummocks are used (n = 10). CH(4) recorded in almost every profile was localised in intense peaks reaching concentrations up to 350 mu M at depths where O(2) was absent. Each CH(4) peak had a coincident CO(2) peak with a minimum mean ratio of similar to 20:1 (CO(2):CH(4)) and we found more CH(4) beneath hollows than hummocks. In statistical comparisons CH(4) concentration and distribution differed significantly between profiles for each depth. We demonstrate that variability found within a single core is at least as great as that between cores collected across the bog. The distribution of CH(4) was negatively correlated with bulk density and in some cases the location of roots matched those of intense CH(4) concentration where bubbles had formed and been trapped. Our comparisons suggest variability in gas distribution is caused by a heterogenous peat structure that controls the movement of gas bubbles and contains localised hotspots of gas production. The small and fine root systems of vascular plants on the peatland surface may cause high levels of methanogenic activity in their vicinity and also represent a physical barrier capable of trapping CH(4) bubbles.
For any incoming editor there are two immediate challenges.
The first is to ensure that the journal continues to
increase in impact in an increasingly competitive and
changing journal market. This can only be done by
ensuring that this journal becomes, or remains, the first
choice outlet for dissemination of important contributions
in the field of insect conservation. A healthy journal has to
have contributions from key scientists with international
reputations, yet at the same time encourage and facilitate
early career scientists to publish in it too. The second
challenge is to reflect on the steer and direction that the
previous editor has given to the journal and to ensure that
the successes of the previous editor serve as a building
block for the future.
Cation availability in peat may limit CH(4) production and microbial activity and thereby impact on rates of organic matter accumulation and the chemical character of the peat. We quantify total, soluble, and exchangeable cation concentrations, Exchange Site Saturation Levels (ESSLs) and organic fractions in bog-peat profiles and compare these with fen peat. Total and soluble cation concentrations are not correlated and these and exchangeable cation concentrations are lower in bog than fen peat. In all sites these vary with depth and the distribution patterns of individual cations are unique. This is explained by variation in ESSL, which is negatively correlated with Cation Exchange Capacity (CEC). Total cation concentrations in bog peat are higher in the top and bottom fractions than in the middle. Soluble concentrations in surface bog peat are low, because cations are trapped due to low ESSL This does not occur in fen peat, with lower CEC and higher ESSL CEC is related to total organic matter content, not just to Sphagnum, which has been invoked as the explanatory variable of high CEC in peat bogs. There is a complexity in the mechanisms controlling cation availability in peat and we suggest that total, soluble and exchangeable cation fractions need to be taken into account in studies of cation limitation of microbial activity in organic soils. CEC may also chelate exo-enzymes, further inhibiting decay processes.
Historically, morphological variation has been used to classify many species (and subspecies) of Lepidoptera. However, some of this variation may be unsuitable for inferring the recent evolutionary history of populations. Genetic data provide an alternative. We examine the morphological and genetic variation within and between British subspecies of Coenonympha tullia (Muller 1764) to test the hypothesis that neutral genetic variation corresponds to morphological variation. We find that most morphological and genetic variation occurs within populations and that those populations designated as subspecies based on morphological characters are not necessarily most closely related for mitochondrial DNA or nuclear DNA (amplified fragment length polymorphisms and allozymes). Thus, the notion that wing spot variation reflects population isolation and therefore genetic differentiation does not hold. The present study highlights the need for genetic data where taxonomy may be based on environmentally plastic or locally adapted characters because such characters will not reflect the true population genetic history.
Clear examples of ignoring landscape corridors are given for allegedly sedentary butterflies observed in the process of dispersing from habitats; these are discussed in the context of the provision of corridors in managing the British landscape for maintaining populations of Lepidoptera.
Historically, morphological variation has been used to classify many species (and subspecies) of Lepidoptera. However, some of this variation may be unsuitable for inferring the recent evolutionary history of populations. Genetic data provide an alternative. We examine the morphological and genetic variation within and between British subspecies of Coenonympha tullia (Müller 1764) to test the hypothesis that neutral genetic variation corresponds to morphological variation. We find that most morphological and genetic variation occurs within populations and that those populations designated as subspecies based on morphological characters are not necessarily most closely related for mitochondrial DNA or nuclear DNA (amplified fragment length polymorphisms and allozymes). Thus, the notion that wing spot variation reflects population isolation and therefore genetic differentiation does not hold. The present study highlights the need for genetic data where taxonomy may be based on environmentally plastic or locally adapted characters because such characters will not reflect the true population genetic history. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 97, 314-327. © 2009 The Linnean Society of London.
Depending on their faunal content islands can function as important 'vehicles' for conservation. In this study, we examine data on 440 butterfly species over 564 European islands in 10 island groups. To determine the status of the butterfly fauna, we have adopted two approaches, island-focused and species-focused, examined using principal components analysis and regression modelling. In the former, we relate species richness, rarity and endemicity to island geography (area, elevation, isolation and location in latitude and longitude); in the latter, species occurrence on islands is examined in relation to distribution, range, range boundaries, and altitudinal limits on the continent as well as species' ecology (number of"/> host plants) and morphology (wing expanse). Species on islands are also assessed for their status on the continental mainland, their distributional dynamics (extinctions, distribution changes) and conservation status (Red Data Book, European Habitat Directive, Species of European Conservation Concern and Bern Convention listing. Unexpectedly, we find that a large fraction of the European butterfly species is found on the islands (63.4%; 59% on small islands) comprising some 6.2% of the land area of Europe. Although species occurring on the islands tend, on the whole, to have lower conservation status and are not declining over Europe, 45 species are endemics restricted to the islands. Species richness shows only a weak locational pattern and is related as expected to isolation from the continental source and island area; but, both rarity and endemicity have distinctive geographical bias to southern Europe, on islands now under increasing pressure from climate change and increasingly intensive human exploitation. The vulnerability of species on islands is emphasised in the relationship of island occurrence (% occurrence and presence/absence of species on any island) with continental distributions. A large proportion of the variation (84%) is accounted by continental distribution, the southern range limit and lower altitudinal limit. Most species (69%) occur on very few islands (< 5%). In view of ongoing species dynamics on islands, migrations and extinctions of species, island repositories of species depend in large part on conservation of butterflies at continental sources. The unique faunas and rare species on islands also depend on appropriate concern being given to the island faunas. Conservation of European islands is thus a two-way process, sustaining sources and conserving island refuges. Residuals from the regressions (islands with more or fewer species, rare and endemic species; species occurring more or less frequently than expected on islands) provide warning signals of regions and islands deserving immediate attention.
The quantification of greenhouse gas sources and sinks is important to understanding the impact of climate change. Methane (CH4) is a potent greenhouse gas, which, on a global scale, is released largely as a product of anaerobic microbial decomposition and predominantly from wetlands. A zone of intense CH4 production just below the water table is thought to contribute significantly to the overall flux from peat bogs. We describe the use of membrane inlet quadrupole mass spectrometry (QMS) to confirm the existence of bubbles, their gaseous concentrations and their localization at a fine spatial resolution within intact peat cores. We use the distribution of the noble gas argon (Ar) and the distinct QMS responses to dissolved and gaseous (bubble) phases to identify trapped bubbles with a resolution of 0.6 mm. Bubbles with CH4 concentrations of up to 20 kPa were widely distributed in the upper 300 mm of the cores with ˆ¼11% of all profiles comprising bubbles. The dissolved concentrations responsible for the bubbles were on average 83±80 Î¼m, indicating lower concentrations relative to other QMS studies. We suggest that if the distinction between dissolved and gaseous phases is not made in studies of CH4 within peat profiles then the prominence of bubbles is likely to result in overestimates of dissolved CH4 concentrations. Fluxes of CH4 from peat as a result of drawdown or other perturbation are likely to be large, rapid and short lived because of bubble burst, and also larger than from peat without bubbles. We suggest that the dynamics of fluxes need to be modelled taking into account both gaseous and dissolved phases. Estimates of potential fluxes that assume CH4 is dissolved are likely to overestimate fluxes if the gaseous phase has not been taken into account.
Multiple transect counts following Butterfly Monitoring Scheme (UKBMS) guidelines and Jolly-Seber estimates of population size were used to monitor the abundance of second generation Lasiommata megera on a single site in southern England. The two methods resulted in different patterns of emergence being detected. The proportion of the population (estimated by Jolly-Seber) recorded with transect counts depended on the time of day and weather with afternoon transect counts best recording the trend in abundance over the flight period, but even then counts recorded a variable fraction of the population (6.2-51.3%). Increasing the frequency with which transect counts are carried out per week reduced variation and increased the fit of transect counts to Jolly-Seber generated population estimates. However, indices of abundance generated from randomly selected transect counts for L. megera within sampling weeks varied 4-fold and indices for other butterfly species were also highly variable. For L. megera, transect count variability is attributed to non-representative placement of the transect route and changes in the behaviour and spatial distribution in relation to population size and season. We suggest that transect counts need to be fully validated before the data are used to monitor changes of butterfly populations at individual sites.
We use field observations in two geographic regions within the British Isles and regression and neural network models to examine the relationship between microhabitat use, thoracic temperatures and activity in a widespread lycaenid butterfly, Polyommatus icarus. We also make predictions for future activity under climate change scenarios. Individuals from a univoltine northern population initiated flight with significantly lower thoracic temperatures than individuals from a bivoltine southern population. Activity is dependent on body temperature and neural network models of body temperature are better at predicting body temperature than generalized linear models. Neural network models of activity with a sole input of predicted body temperature (using weather and microclimate variables) are good predictors of observed activity and were better predictors than generalized linear models. By modelling activity under climate change scenarios for 2080 we predict differences in activity in relation to both regional differences of climate change and differing body temperature requirements for activity in different populations. Under average conditions for low-emission scenarios there will be little change in the activity of individuals from central-southern Britain and a reduction in northwest Scotland from 2003 activity levels. Under high-emission scenarios, flight-dependent activity in northwest Scotland will increase the greatest, despite smaller predicted increases in temperature and decreases in cloud cover. We suggest that neural network models are an effective way of predicting future activity in changing climates for microhabitat-specialist butterflies and that regional differences in the thermoregulatory response of populations will have profound effects on how they respond to climate change.
A basic assumption in conservation is that comparable data are available for species to facilitate risk assessment of extinction. However, the capacity for carrying out cross-species comparisons for abundances and distributions among butterflies depends on the absence of bias in recording and monitoring or the existence of appropriate techniques for removing bias. Here, we investigate potential bias in cross-species comparisons for the apparency of butterfly adults (wing colour, size and behaviour) in three pivotal UK datasets: dates of discovery, Butterfly Monitoring Scheme (BMS) transect measures of abundance and Butterflies for the New Millennium (BNM) national recording scheme. Bias is found in all three datasets. Discovery date is affected by wing colour and size, BNM recording by adult behaviour and wing colour and BMS monitoring by adult behaviour. The nature and degree of bias differs between uncorrected cross-species comparisons and those with the application of phylogenetic contrasts. The findings urge caution in using these datasets for cross-species analysis without improvements and standardisation of recording and monitoring and the development of techniques to adjust for biases, in particular the use of suitable comparative techniques. The latter requires the construction of a molecular phylogeny for butterflies.
Current definitions of habitat are closely allied to the concept of patch and matrix. This concept is, for instance, central to the prevailing metapopulation models of population dynamics. But, butterfly population dynamics, mobility and spatial structure can only properly be understood in the context of a resource-based definition of habitats. In criticising current definitions of habitat, we illustrate how habitat is best understood in terms of resource distributions. These transcend vegetation-based definitions of habitat and lie at the root of life history strategies, the vulnerability of butterflies to environmental changes and extinction, and govern conservation status. We emphasise the need for a resource-use database and demonstrate the shortcomings of current data for conserving butterflies; patch based definitions of habitats are inappropriate for some species and for others do not provide a universal panacea, inadequately explaining spatial occurrence when scaled over space and time. A resource-based habitat definition challenges the bipolar, patch vs. matrix view of landscape; the alternative is to view landscape as a continuum of overlapping resource distributions. We urge greater attention to the details of butterfly behaviour and resource use as the keys to understanding how landscape is exploited and therefore to successful conservation at the landscape scale.
Although butterfly distributions are known to be positively correlated with the number of larval hostplants used it is not known to what extent larval hostplant number uniquely influences butterfly distributions and to what extent effects are indirect through other variables. This issue is central to understanding the part generalism and specialism in host use play in organism persistence and conservation. Here, we have modelled the links between larval hostplant number and butterfly distributions using data from the UK. The model identifies the key variables that connect number of hostplants used by butterflies and the size of butterfly distributions. Significant correlations between variables give support to the model. Access to more hostplants is shown to affect a number of resource and life history variables impinging on butterfly population abundances and butterfly distributions. Butterfly distributions are largely accounted for (R 2>81%) by a set of resource and life history variables linked to numbers of hostplants: biotope occupancy, nectar sources used, utilities (the number of structures used by each life-cycle stage) and hostplant abundance. Application of partial regression demonstrates that the unique contribution of hostplant number to butterfly distributions is relatively small (R 2 = 14% to 33%), indicating that host use generalism has a limited direct impact on distributions. The modest correlations linking variables within the model illustrates that specialist phytophage feeders have a number of potential, distinct outlets, via resource and life history variables, to compensate for lack of supplementary larval hosts within their geographical ranges and enabling them to persist. Variables in the model each have considerable independence of action; without this, specialist feeders would have difficulty in expanding their distributions and acquiring new hosts, functionally-linked processes affecting evolutionary dynamics and persistence. We also question the nature of a direct functional link between local population abundance and distributions. Our model suggests a more complex functional relationship with implications for conserving insect herbivores.
Although butterfly distributions are known to be positively correlated with the number of larval hostplants used it is not known to what extent larval hostplant number uniquely influences butterfly distributions and to what extent effects are indirect through other variables. This issue is central to understanding the part generalism and specialism in host use play in organism persistence and conservation. Here, we have modelled the links between larval hostplant number and butterfly distributions using data from the UK. The model identifies the key variables that connect number of hostplants used by butterflies and the size of butterfly distributions. Significant correlations between variables give support to the model. Access to more hostplants is shown to affect a number of resource and life history variables impinging on butterfly population abundances and butterfly distributions. Butterfly distributions are largely accounted for (R>81%) by a set of resource and life history variables linked to numbers of hostplants: biotope occupancy, nectar sources used, utilities (the number of structures used by each life-cycle stage) and hostplant abundance. Application of partial regression demonstrates that the unique contribution of hostplant number to butterfly distributions is relatively small (R = 14% to 33%), indicating that host use generalism has a limited direct impact on distributions. The modest correlations linking variables within the model illustrates that specialist phytophage feeders have a number of potential, distinct outlets, via resource and life history variables, to compensate for lack of supplementary larval hosts within their geographical ranges and enabling them to persist. Variables in the model each have considerable independence of action; without this, specialist feeders would have difficulty in expanding their distributions and acquiring new hosts, functionally-linked processes affecting evolutionary dynamics and persistence. We also question the nature of a direct functional link between local population abundance and distributions. Our model suggests a more complex functional relationship with implications for conserving insect herbivores. © Springer 2005.
Among Palaearctic Satyrinae, Melanargiaspecies, typified by M. galathea, are highly unusual. Their bright white and black wing colouration is more typical in appearance of pierines than of satyrines. Previously, we suggested that M. galatheabehaves more like a pierine than a satyrine (Dennis and Shreeve, 1988). Bearing in mind that pierinae are chemically defended against avian predators (Rothschild et al. 1977), the progression in this line of thinking was that perhaps the bright coloration and behaviour of Melanargia species makes them Batesian mimics of Pierinae. As these attributes are clearly ancient, we considered that other brightly coloured, similarly behaving and chemically defended groups of butterflies (e.g., Zerynthia, Papilionidae) could be possible models of Melanargiaspecies, particularly as they were more likely to share the same biotopes in Europe. Recently M. galatheahas been discovered to be toxic to avian predators (R. Nash in Rothschild, 2001). The alternative suggestion thus arises that Melanargiais chemically defended in its own right and has developed a parallel package of behaviour and defences to those in Pieridae and Papilionidae, possibly extending to Müllerian mimicry. As more information gathers on this unusual satyrine butterfly taxon, what becomes clear in all this speculation is that nothing is clear at all; questions are accumulating and few unequivocal answers have emerged.
1. To determine whether rarity and decline is linked to organism ecology, associations have been examined between butterfly larval host-plant competitive, stress-tolerant, ruderal (C-S-R) strategies and butterfly biology.
2. Associations have been sought between mean C-S-R scores for larval host plants with butterfly life history, morphology and physiology variables, resource use, population attributes, geography, and conservation status. Comparisons are carried out across species and controlled for phylogenetic patterning.
3. Butterfly biology is linked to host-plant strategies. An increasing tendency of a butterfly's host plants to a particular strategy biases that butterfly species to functionally linked life-history attributes and resource breadth and type. In turn, population attributes and geography are significantly and substantially affected by host choice and the strategies of these host plants.
4. The greatest contrast is between butterfly species whose host plants are labelled C and R strategists and those whose host plants are labelled S strategists. Increasingly high host-plant C and R strategy scores bias butterflies to rapid development, short early stages, multivoltinism, long flight periods, early seasonal emergence, higher mobility, polyphagy, wide resource availability and biotope occupancy, open, areally expansive, patchy population structures, denser distributions, wider geographical ranges, resistance to range retractions as well as to increasing rarity in the face of environmental changes. Increasing host-plant S strategy scores have reversed tendencies, biasing those butterfly species to extended development times, fewer broods, short flight periods, smaller wing expanse and lower mobility, monophagy, restricted resource exploitation and biotope occupancy, closed, areally limited populations with typical metapopulation structures, sparse distributions, and limited geographical ranges, range retractions, and increased rarity.
5. Species with S strategy host plants are species vulnerable to current environmental changes and species of conservation concern.
New data appearing in the second of two French atlases within one and a half years confirm that there was substantial under-recording of butterfly species in France for the production of the first atlas, particularly in the south and west of the country. Under-recording is still a prominent feature of the southwest region and eastern border. The new data also reveal contractions in the ranges of 60 species suggesting real losses as a result of regional extinction especially in the north of the country. This finding links adjacent areas of ongoing high regional extinction in continental European Lepidoptera extending from the Netherlands through Belgium into northern France. The new data also demonstrate that predictions of species numbers and species incidences based on records in the first atlas, using regression techniques on geographical and neighbourhood variables, have been largely successful (76% correct prediction of new records for départements). This supports the application of such techniques to targeting surveys for mapping spatial units and species to improve atlas databases; the recent rapid changes in distributions underlines the importance of having a suitable framework for continuing recording after atlas publication.
The habitat is the basic unit for developments in life history, population dynamics, landscape ecology and conservation of organisms. It is frequently treated as a particulate, invariant and homogeneous entity (a patch). Here we examine the implications of using this concept of habitat in butterfly biology. In doing so, we suggest the alternative approach of applying a functional resource-based concept of habitat. This recognises the fundamental requirements of organisms, consumables and utilities, the latter describing suitable environmental conditions as well as essential substrates. We argue that a resource-based concept is critical for butterfly conservation and call for the development of a resource database on butterfly biology.
1. The thermal environment at the scale in which most species exist is largely unknown, and thus the majority of physiological models is based on meteorological measures of ambient temperature. 2. The use of artificial neural networks in ecological analysis is promoted by using them to model microhabitat temperature. 3. The performance of conventional multiple linear regression is compared with that of artificial neural networks in predicting the temperature profiles of two different microhabitats using ambient temperature, solar radiation, and wind speed as input (independent) variables. 4. In both cases, the artificial neural networks showed a lower mean absolute residual error than multiple linear regression (0.95 °C compared with 1.41 °C, and 0.29 °C compared with 0.50 °C) and a higher correlation (r2) between predicted and observed values (0.832 compared with 0.668, and 0.884 compared with 0.670). 5. An artificial neural network developed to include a microhabitat patch description based on height within patch, substrate, and four classes of per cent vegetation cover performed well (r2 = 0.933, prediction error 95% confidence limits =± 2.5 °C). 6. It is suggested that artificial neural networks are more appropriate than conventional regression-based approaches for estimating microhabitat temperature.
We use data from the French national butterfly atlas to compare the potential of direct geographical and neighbourhood models to account for numbers of species and incidence of species in French départements. Direct geographical models use data on latitude, longitude and altitude, whereas neighbourhood models use information from adjacent areas. Both geographical models and neighbourhood models account for a large proportion of the variance in species richness (68–78%). However, neighbourhood models are more successful than models based solely on simple geographical variables. A large number of individual species distributions are accounted for by logistic and autologistic regression models (222 of 246 species, 90.2%). The autologistic models incorporate information on neighbouring areas. The exceptions are rare species, five of six of which occur in a single administrative unit only (2.4%), or virtually ubiquitous species found in >90% of units (7.3%). Autologistic models dominate logistic models in accounting for species incidences using stepwise logit regressions, neighbourhood variables appearing in 64.5% of successful species models (absent in 22.8%) and then always entering first. A simple neighbourhood (distance-unweighted) measure (C2) dominates more models (89 of 246 species, 36.2%) than a distance-weighted neighbourhood measure (C1; 77 of 246 species, 31.3%). The models are here demonstrated to be potentially valuable for identifying under-recording and losses from regional extinction and for filling gaps in recording. The findings reveal substantial, apparent, losses of species in western and northern France as well as substantial discrepancies (differences) in numbers of species, for some administrative units (départements) and for both post-1970 and total records, compared with numbers predicted to occur. We use two distinct approaches on total species and individual species to provide comparative estimates of the numbers of species expected within spatial units and we present the number of additional units in which species are expected to occur. The probabilities for these species in French départements are available on Web site:
We use data from the French national butterfly atlas to compare the potential of direct geographical and neighbourhood models to account for numbers of species and incidence of species in French départements. Direct geographical models use data on latitude, longitude and altitude, whereas neighbourhood models use information from adjacent areas. Both geographical models and neighbourhood models account for a large proportion of the variance in species richness (68-78%). However, neighbourhood models are more successful than models based solely on simple geographical variables. A large number of individual species distributions are accounted for by logistic and autologistic regression models (222 of 246 species, 90.2%). The autologistic models incorporate information on neighbouring areas. The exceptions are rare species, five of six of which occur in a single administrative unit only (2.4%), or virtually ubiquitous species found in >90% of units (7.3%). Autologistic models dominate logistic models in accounting for species incidences using stepwise logit regressions, neighbourhood variables appearing in 64.5% of successful species models (absent in 22.8%) and then always entering first. A simple neighbourhood (distance-unweighted) measure (C) dominates more models (89 of 246 species, 36.2%) than a distance-weighted neighbourhood measure (C; 77 of 246 species, 31.3%). The models are here demonstrated to be potentially valuable for identifying under-recording and losses from regional extinction and for filling gaps in recording. The findings reveal substantial, apparent, losses of species in western and northern France as well as substantial discrepancies (differences) in numbers of species, for some administrative units (départements) and for both post-1970 and total records, compared with numbers predicted to occur. We use two distinct approaches on total species and individual species to provide comparative estimates of the numbers of species expected within spatial units and we present the number of additional units in which species are expected to occur. The probabilities for these species in French départements are available on Web site: http://www.brookes.ac.uk/schools/bms/research/data/ecology/butterfly.html. © 2002 Elsevier Science Ltd. All rights reserved.
Previously, Pieris napi (Linnaeus, 1758) within the British Isles has been divided into different subspecies and also separated from mainland European populations on the basis of androconial and wing morphology variation. Using image analysis we obtained quantitative data on androconial scale shape measurements and wing morphology characters (size and colour pattern elements) of P. napi from the British Isles and France (wing morphology only) to examine the subspecific status of P. napi within the British Isles. Androconia are variable in shape but this variation is normally distributed. There is no basis for describing different scale types within the British Isles. Variation within populations in Scotland and southern England is greater than between regions and there is no basis for using androconial measures to describe Scottish specimens as subspecies. Wing size, shape and colouration are variable within populations and variation in particular characters is not consistent between generations or geographic regions. Wing morphology is a poor taxonomic tool for describing regional forms. We conclude that there is no evidence to divide P. napi in the British Isles into subspecies or to differentiate populations in the British Isles from mainland Europe.
Data for butterflies on 31 islands are used to predict the number of species and the incidence of species on a further 33 islands in the Aegean archipelago using geographical data. Predictions of species incidence are extremely high (92%). Successful predictions are, however, influenced by the frequency of species over the islands; correct predictions are far less successful for rare species. New records continue to be made for islands used to make predictions. This is to be expected for a number of reasons, particularly the low population density of many species on Greek islands and the fact that systematic and continuous recording has yet to be made on these islands. It is expected that predictions will improve with the incorporation of data on mainland source populations and environmental agents.
We classify British butterflies using 136 non-biotope associated binary state ecological attributes describing all stages of butterfly life-cycles. Using cluster analysis we identify two groups of woodland species, a group occurring in tall open grassland, another group associated with short sward herb-rich grassland, and a ruderal group. Principal Component and Factor analyses (4 factor solution) are used to identify ecological attributes that determine species groupings. No single attribute or attribute type is responsible for the groupings, which are also insensitive to hostplant type. We use presence/absence data from Butterfly Monitoring Scheme transects in southern Britain to test our classification. On the basis of adult occurrences, similarities within two of the four groups identified from PCA are greater than between groups. Exclusivity between species pairs is also more frequent between groups than within groups. Species' ranges, distributions, biotope range, dispersal ability and recent decline in abundances differ between groups identified by their factor loadings. Ruderal species have large ranges, abundances, extensive mobilities and show little recent decline. The group associated with short sward grassland have the lowest mobilities, and the smallest distributions within their geographic ranges. True woodland species have the smallest biotope range, and the species associated with open areas have the second smallest decline in their distributions. Our ecological classification identifies characteristics of species that determine their habitat requirements and could serve to predict the response of species groups to environmental change on the basis of their ecological attributes. Our method may be of use in identifying the relative importance of ecological attributes of less-well studied taxa and be applicable in less well known geographic regions.
Aim We compare the influence of contemporary geography and historical influences on butterfly diversity for islands in the Aegean archipelago.
Location The Aegean archipelago (Greece) and two islands (Cyprus and Megisti) in the Levantine Sea.
Methods Thirty-one islands were examined. Data are taken from own surveys (Coutsis and Olivier) and from the literature. Stepwise multiple regression is used to determine relationships between species richness, frequency, rarity and endemicity against potential geographical predictors. Stepwise logit regression is used to determine geographical predictors of species incidence on islands. Inter-island and inter-species associations have been examined using multivariate ordination and clustering techniques.
Results The Aegean butterfly fauna is characterized by decreasing diversity and rarity, and increasing homogeneity, from the periphery to the present geographical centre of the archipelago (Cyclades). Diversity and rarity are shown to relate closely to species richness, and species richness, in turn, is largely explained by contemporary geography, particularly the degree of isolation from the nearest mainland sources of Greece or Turkey, and island dimensions. Islands towards the centre of the archipelago are characterized by a group of mobile species (n ≥ 20 species) with extensive ranges across Europe; species that would have recolonized Santorini (Thira) following the VI6 eruption there c. 1630 bc. Endemic components, indicative of autochthonous evolutionary events, are few (5% of species are endemic) compared to known sedentary organisms (molluscs and isopods), but exceed those for more mobile animals (i.e. birds); their distribution is mainly confined to large isolated islands along the Aegean arc (i.e. Kriti) and in the Dodecanese group.
Main conclusions Contemporary geography, i.e. processes currently operating in ecological time, dominates butterfly diversity gradients (species richness, frequency, rarity and incidence) in the archipelago. Two reasons are suggested to account for the lack of endemism and the pattern of decreasing diversity into the Cyclades. First, relict butterfly elements may have become extinct on all but a few larger islands, particularly from environmental changes since the Neolithic (fire and overgrazing). Second, colonization from the continental landmasses is ongoing with more mobile species transferring even to the most isolated islands.
Aim: We compare the influence of contemporary geography and historical influences on butterfly diversity for islands in the Aegean archipelago. Location: The Aegean archipelago (Greece) and two islands (Cyprus and Megisti) in the Levantine Sea. Methods: Thirty-one islands were examined. Data are taken from own surveys (Coutsis and Olivier) and from the literature. Stepwise multiple regression is used to determine relationships between species richness, frequency, rarity and endemicity against potential geographical predictors. Stepwise logit regression is used to determine geographical predictors of species incidence on islands. Inter-island and inter-species associations have been examined using multivariate ordination and clustering techniques. Results: The Aegean butterfly fauna is characterized by decreasing diversity and rarity, and increasing homogeneity, from the periphery to the present geographical centre of the archipelago (Cyclades). Diversity and rarity are shown to relate closely to species richness, and species richness, in turn, is largely explained by contemporary geography, particularly the degree of isolation from the nearest mainland sources of Greece or Turkey, and island dimensions. Islands towards the centre of the archipelago are characterized by a group of mobile species (n ≥ 20 species) with extensive ranges across Europe; species that would have recolonized Santorini (Thira) following the VI6 eruption there c. 1630 BC. Endemic components, indicative of autochthonous evolutionary events, are few (5% of species are endemic) compared to known sedentary organisms (molluscs and isopods), but exceed those for more mobile animals (i.e. birds); their distribution is mainly confined to large isolated islands along the Aegean arc (i.e. Kriti) and in the Dodecanese group. Main conclusions: Contemporary geography, i.e. processes currently operating in ecological time, dominates butterfly diversity gradients (species richness, frequency, rarity and incidence) in the archipelago. Two reasons are suggested to account for the lack of endemism and the pattern of decreasing diversity into the Cyclades. First, relict butterfly elements may have become extinct on all but a few larger islands, particularly from environmental changes since the Neolithic (fire and overgrazing). Second, colonization from the continental landmasses is ongoing with more mobile species transferring even to the most isolated islands.
The presence or absence of the grayling butterfly, Hipparchia semele (L.), on British and Irish islands has been studied using logistic regression and discriminant analysis. Two subgroups of islands, one classed as having records of vagrant H. semele and the second occurring beyond the range margin for the species in northern Britain, appear as outliers in plots for the three variables island area, isolation and source population size. Although inclusion of the subgroups does not affect the significance of parameter estimates, they do substantially influence explained variances and the classification of individual islands. On the basis of the three variables listed, resident populations of the butterfly on both subgroups of islands are shown to be improbable. When the variables are considered individually, resident H. semele populations are predicted for islands with vagrants as a function of isolation and for those beyond the range margin as a function of area. However, in both cases colonization is unlikely, limited by resources in the former case and by environmental conditions in the latter. The implications for island and metapopulation studies, which focus on patch occupancy, is that both habitat quality and the breeding status on patches should be assessed for the calculation of parameter estimates.
European butterfly species have been classified, using four multivariate classification techniques, to faunal groups (a collection of species having similar distributions) each group having a unique geography (faunal element). Concordance occurs for 94% of species for at least three of the techniques. The faunal groups are brassed in geography, endemicity and taxonomic affiliation, indicating that they have historical and evolutionary significance. The inference is that a species by belonging to one faunal group, rather than to another, has a higher probability of being an endemic, and if it is not an endemic, then of evolving into one. This probability is influenced by affiliation to higher taxa, such as butterfly families, and thus by phylogenetic constraints. We argue that the fidelity of a species to a faunal element will affect its evolutionary pathway since, by belonging to a faunal element, a species is subject lo the distinctive processes linked to a unique landscape and its environmental conditions. Species have the capacity of switching between faunal groups owing to environmental changes impinging on their geographical ranges and epigenotypes. However, transfer of species across different groups are not of equal likelihood, being greatest between contiguous land elements and least between those restricted to islands. We suggest that conservation biology gives more attention to faunal structures: faunal groups have unique geography, are vulnerable to different macroevolutionary pressures and effectively underpin community assemblages within specific biotopes.
Examines the effects of island area, isolation and source population size on the presence of the grayline butterfly hipparchia semele lepidoptera on British and Irish offshore islands. Relationship between number of species on island and at nearest sources and incidence of species on islands and at nearest sources; Predictor importance of isolation than island area.
Records of Hipparchia semele on British and Irish islands have been modelled against island area, isolation (sea and land distance) and the size of the nearest potential source populations. All three variables have been found to contribute significantly to the presence or absence of H. semele on the islands. Isolation is a more significant predictor than island area. This result differs from the multiple species case where area was found to be a more important influence than isolation. Records on islands are also shown to depend on the size of populations at the nearest sources; this underpins the relationships identified for the multiple species case, first, between the number of species on islands and at nearest sources and, second, between the incidence of species on islands and at nearest sources. There are clear indications that smaller islands may become increasingly marginalized for H. semele; with ongoing habitat loss, because isolation increases and source populations become sparser, the probability of H. semele recolonizing islands also decreases.
To distinguish between the influences of area and isolation on the butterfly faunas of British islands two approaches are adopted. First, species richness is related to island area, isolation and the size of the faunal source. Neither area nor isolation account for much variance in species richness, though area is more important than isolation. In contrast, species richness corresponds closely to the size of the faunal source on nearby islands and to that at proximate locations on adjacent mainlands. The second approach relates the incidence of species on islands to their ecological attributes. A very close relationship is found between species incidence on islands and those ecological variables that measure potential for migration and colonization and that resist extinction. The implications are that the majority of British islands in this survey are insufficiently isolated to prevent intermittent migrations of butterflies to them or so small as to generate frequent extinctions. Independent data indicate the capacity of many resident species to migrate distances in excess of the isolation of most of the islands. Some evidence also exists for the long-term survival of species on islands; important considerations in this respect are that most islands in the survey are large compared to habitat patches sustaining species on mainland Britain and that substantial portions of islands are retained in early seral stages or comprise long-lived stable habitats (e.g. peat mosses) that are particularly suitable for many British species.
Marginality describes the impact that environmental and landscape factors have in decreasing the probability of population survival and persistence. It may be imposed by extreme conditions or resource scarcity. Typically, it affects populations at the range edge but can also affect populations within the core of ranges, and produces a number of symptoms: characteristically demographic, but also morphological, physiological, biochemical and genetic. In this paper, the causes and effects of marginality on British butterflies are compared in edge and centre of range populations. Issues of temporal and spatial scales are examined, as is the relevance of marginality to the conservation of single and multiple species populations. The recognition of marginality questions the appropriateness of many so-called spatially realistic models of populations and highlights areas of research which have hitherto been ignored. Projected changes in land use and climate have implications for marginality in core and peripheral populations; in view of this, current scales of mapping are found to be unsuitable for monitoring fragmentation and the increasing marginalization of butterfly species in the British landscape.
Marginality describes the impact that environmental and landscape factors have in decreasing the probability of population survival and persistence. It may be imposed by extreme conditions or resource scarcity. Typically, it affects populations at the range edge but can also affect populations within the core of ranges, and produces a number of symptoms: characteristically demographic, but also morphological, physiological, biochemical and genetic. In this paper, the causes and effects of marginality on British butterflies are compared in edge and centre of range populations. Issues of temporal and spatial scales are examined, as is the relevance of marginality to the conservation of single and multiple species populations. The recognition of marginality questions the appropriateness of many so- called spatially realistic models of populations and highlights areas of research which have hitherto been ignored. Projected changes in land use and climate have implications for marginality in core and peripheral populations; in view of this, current scales of mapping are found to be unsuitable for monitoring fragmentation and the increasing marginalization of butterfly species in the British landscape.
Previously published in hardback and now made available in paperback, this ground-breaking book is a must for all interested in butterflies, whether as conservation biologist, amateur or professional entomologist or as a student studying the phenomenon of butterfly populations as part of a number of biology, ecology or conservation courses.
Recently, many British butterflies have suffered severe declines whole others have flourished and expanded in range. This is the first book to describe the results from a British scheme to monitor butterflies during this period of change. The Monitoring Scheme, initiated in 1976 by the senior author is based on frequent counts at some 90 sites throughout Britain. The combined efforts of both amateurs and professionals have thus produced a dataset with no equivalent elsewhere in the world. The book therefore provides a unique perspective on trends in numbers, extinction and foundation of populations; flight periods, local distributions, migration and other aspects of population ecology. Practical problems encountered during the conservation of butterflies of individual sites are outlined. The relevance of this monitoring for an understanding of the effects of the weather - climatic warming - is described.
Insect Ecology and Conservation
Software tools for environmental monitoring
Fellow of the Royal Entomological Society
Member of Chartered Institute of Ecology and Environmental Management
Member of the British Ecological Society
Member of NERC Industrial Case Awards Panel (2016)
I was engaged in a national programme (2012-16) run by Natural England to assess the quality of Sites of Special Scientific Interest using invertebrate species. This research based consultancy work was part of the periodic reviewing of the state of biodiversity in England
SHREEVE, T.G.2107-18 Participant in the sDiv workshops 'Separating Environmental Changes and their effects on Community traits in European butterflies'. german Centre for Integrative Biodiversity Research (iDiv), Lepzig.(invited participant).SHREEVE, T.G. 2015. Butterflies as indicators of biodiversity change. Inaugural meeting of the Legambiente Italia (Italian National Parks) Tuscan Island conservation initiative. University of Turin. (invited keynote)SHREEVE, T.G., DAPPORTO, L. DENNIS, R.L.H. & DOVER, J. 2014. Applying the resource based concept to corridors and barriers in biodiversity conservation: mending the matrix 7th International Symposium of Butterfly Conservation, Reading, April 2014.SHREEVE, T.G. 2012: The Challenges of Introducing and Maintaining Taxonomy and Identification in undergraduate and MSc courses. The Linnean Society, London, (invited presentation)SHREEVE T.G. 2010 Landscapes and corridors for insect conservation. 6th International Symposium of Butterfly Conservation, Reading, April 2010 (invited)ALMAN, S., GIBBS, M., SHREEVE, T. & BREUKER, C. 2010. Oviposition behaviour in the speckled wood butterfly (Pararge aegeria, L.). 16th Annual European Meeting of PhD students in Evolutionary Biology, Wierzba, Poland,, 23-28 May 2010. SHREEVE T.G. 2009. Improving insect monitoring workshop presentation. South east region biological recorders workshop. April 2009 (invited)HARKER R. & SHREEVE. T G 2008 The decline and conservation of the wall brown butterfly Lasiommata megera. Butterfly Conservation one day workshop on the use of biological monitoring data, Birmingham, March 2008. (Invited) SHREEVE, T.G. 2007 Ecological classification, resources and butterfly occurrence. Invited presentation to 3 day East European Butterfly Conservation Workshop, University of South Bohemia, Czech Republic, May 2007 (invited).